Unitum Imperii
The Unitum Imperii (literally "United Empire") was a major empire in Equestria during the Great Pony War. Despite it's major influence and power, the empire is only known to the few who serve in the Shadow Guard prior to the Midnight revealing the true history of Equestria. The Unitum Imperii was formed by Vivaro after he started gaining a following of Ponies who were sick of the damage caused by the Unicorns, Pegasi and Earth Ponies during the Great Pony War. As Vivaro gained more and more followers (referred to as the Sectatores meaning "Followers") he eventually chose to turn the small camp he called home into a thriving town, then a city, and then the centre of an empire. This all took place in Perpetua Libertas ("Eternal Freedom"), which is now known as Everfree City. The unique feature behind the Unitum Imperii was the fact that all kinds of Pony were welcome to join it. This allowed Pegasi, Earth Ponies and Unicorns who did not care for the hatred of the other races to come together and live in harmony, hence "United Empire." As the Unitum Imperii grew in strength it began to gain more resemblance to the Earth-born Roman army, including their weaponry and tactics as well as their primary language; Latin. Eventually it gained enough power to challenge the three major factions directly, and thus the Great Pony War expanded as these new and highly dangerous warriors joined the fray under a new flag, that of two swords crossing over a lightning bolt. Not only that; but the leader of the Unitum Imperii (Emperor Vivaro himself) was almost always present in battle, with his ability to control lightning as well as his control of Magic both pure and Dark, combined with his flying skills, made his forces incredibly strong to the point of being borderline unstoppable. The Unitum Imperii's first major foe was actually Prince Orion, the older brother of Celestia and eldest child of Queen Faust who wanted to claim the throne he thought he had been cheated. As he had not yet made an impression on her, Faust asked Vivaro to help deal with the threat. Vivaro did so but despite Faust asking him to return her only son to her, Vivaro killed his defeated foe as the tradition of the Unitum Imperii indicated he should, with no regrets or care about what he had done. Years after their insurrection the Unitum Imperii gained a splinter of spies and scribes known as the Vigilate Umbra, known now as the Shadow Guard. The purpose of the Vigilate Umbra was to house the truth and archive histories that would otherwise be lost, as well as acting as counter-espionage and the exact polar opposite to the "Silent Watch" (referred to by the Unitum Imperii as the "Silens Vigilate") that served the Dawn, the faction of Queen Faust. Once Queen Faust realised Emperor Vivaro was becoming a great danger to her throne she used the revelation of the Earth Ponies, Pegasi and Unicorns to unite them and stand against Vivaro as an overwhelming army. Despite this, the Unitum Imperii did not falter and seemed to only grow stronger with every passing battle. Despite their massive influence and power, the Unitum Imperii slowly crumbled shortly after Emperor Vivaro seemingly vanished, with no knowledge of his whereabouts ever being uncovered. Eventually only the Vigilate Umbra remained, and became the mysterious Shadow Guard who apparently still served Tenebris Vigil (Dark Watcher), the deity of the Unitum Imperii.